package com.xiaotu.singleton.type2;

/**
 * @author 张晓
 * @create 2020-06-18 15:57
 */
public class SingletonTest02 {

    public static void main(String[] args) {
        //测试
        Singleton instance = Singleton.getInstance();
        Singleton instance2 = Singleton.getInstance();
        System.out.println(instance == instance2);

        System.out.println("instance.hashCode()=" + instance.hashCode());
        System.out.println("instance2.hashCode()=" + instance2.hashCode());

    }

}

//饿汉式（静态变量）
class Singleton{

    //1.构造器私有化，外部不能new
    private Singleton(){
    }

    //2.本类内部创建对象实例
    private static final Singleton INSTANCE;

    //在静态代码块中创建单例对象
    static {
        INSTANCE = new Singleton();
    }


    //3.提供一个公有的静态方法，返回实例对象
    public static Singleton getInstance(){
        return INSTANCE;
    }
}